[lmi] wx-2.8.9: warnings that are trivial to fix

[Greg Chicares]

Here are the only two warnings I got when building wx-2.8.9 with
MinGW gcc-3.4.4 (aside from pesky warnings in libstdc++):

../src/msw/listctrl.cpp:2470:5: warning: "_MSC_VER" is not defined
../src/msw/listctrl.cpp:2491:5: warning: "_MSC_VER" is not defined

Here are those two lines:

2470 #if _MSC_VER >= 1400 && _MSC_VER < 1500
2491 #if _MSC_VER >= 1400 && _MSC_VER < 1500

I'd suggest first testing whether that macro is defined, for example
as is done here:

utils.cpp:    #if !(defined(_MSC_VER) && (_MSC_VER > 800))

This is not an actual problem for me: I don't build wx with
'-Werror' or '-pedantic-errors'.